1. Field of the Invention
The present invention is in the field of optical devices, particularly an optical assembly for a night vision device. More particularly, the present invention relates to a night vision weapon sight having an image intensifier tube. The night vision weapon sight is usable in day light as well as at night. Still more particularly, the present invention relates to such a night vision weapon sight having an improved focus locking assembly for an objective lens of the sight. Also, the present invention relates to a method of making such a night vision weapon sight.
2. Related Technology
A conventional night vision weapon sight is known in accord with U.S. Pat. No. 4,417,814, issued Nov. 29, 1983 to Darrel Doliber. The weapon sight taught by the Doliber patent is believed to include an objective lens or lens assembly admitting light to an image intensifier tube. The image intensifier tube provides a visible image, which at a combiner mirror is combined with light from a reticle injector. The image from the image intensifier tube, and the light from the reticle injector are presented together to a user of the Doliber device via an eyepiece lens. The reticle light is focused to be superimposed on the image from the image intensifier tube, so as to provide a reticle point or aiming point. The Doliber patent is believed to not provide any information about how the objective lens or lens assembly of the sight is focused.
Other conventional weapon sights are known in accord with U.S. Pat. Nos. 5,272,514, issued Dec. 21, 1993 to Amotz Dor; and 5,497,266, issued May 5, 1996 to Larry D. Owen. Each of these patents is believe to teach at least one embodiment of the sight disclosed in which the sight includes an image intensifier tube. However, neither of these patents is believed to disclose an objective focus locking assembly for the sight.